Form dressing assembly



D. J. WALLACE ETAL. 2,827,037

March 18, 1958 FORM DRESSING ASSEMBLY File'd Dec. 13, 1954 United States Fatent none/r nan-sense ASSEMBLY Donald J. Wallace and Leo Catallo, Detroit, Mich.,,as'- signors' to Wheel Tracing Tool Company, Detroit, Mich, a corporation of Delaware Application December 13,1954, Serial No. 474,909

The present invention relates to a. form dressing assembly and process of form dressing. and more particularly relates to form dressing of grinding wheels including apparatus for properly form dressing the peripheral contour thereof to the preselected configuration and the process of so form dressing the same.

One of the outstanding features of the present invene tion is its adaptability for form dressing of grinding wheels, generally, such as for form dressingwheels of a single grinding wheel mechanism. as well as for form. dressing wheels of centerless grinders. Such form dressing may be accomplished most easily and efliciently in accordance with the principles of the present invention since the invention contemplates forming a segmental cylindrical form dressing tool with a peripheral contour on the arcuate face thereof corresponding reversejly to the contour of the working face of the grinding wheel or wheels to be form dressed, and'oscillating the tool arcuately about a relatively fixed center while the same is in. engagement with the grinding wheel;

Heretofore, many various devices have been devised for form dressing. a grinding wheel but many of these have. proved to be somewhat ineflicient and. unsatisfactory since they employed stationary tools or rotary tools which were not power actuated or they employed single point dressing toolson mechanisms which were devised to follow t'emplets as accurately as possible; The templettype of form dressing has, in many instances, been unsatisfactory commercially since it required expensive ap paratus and setup, the need of which is completely obviated by the present invention.

Other forms of dressing grinding wheels include such processes as crush dressing or the like and these also have proven, in many instances, to be unsatisfactory because they did not provide the high degree of accuracy of: dressing that is often desired and which may be obtained by form dressing or through the use of diamond point tools which will cut the abrading wheel or grinding, wheel to the required shape rather than to crush: the resin bonding of the wheel.

It is, therefore, one of the important features of the presentinvention to provide new and improved apparatus and processes for form dressing abrading'wheels such as. grinding wheels or the like to a true and accurate. peripheral contour.

Another important feature of the present invention is to provide new and improved form dressing apparatus for dressing abrasive grinding wheels to a true and accurate peripheral contour with a single arcuately oscil-- lating dressing tool which has a segmental peripheral contour cooperatively opposite to that which is to be imparted to the grinding wheel and the same as that which is to be imparted to the final workpiece by the grinding wheel.

Still another object of the present invention is to provide new and improved form dressing apparatus wherein theform dressing tool has an arcuate face or a segmental cylindrical face and is oscillated about a fixed center on the dressing device.

2,827,037 Patented Mar. 18, 1958 ice Still. another objectof the present. invention is. to provide anew and improved process: of form dressing the periphery of an abrasive wheel such-as a grinding wheel or thelike by engaging the. same with a. form dressing tool having a peripheral configuration opposed to that which is to be imparted to the grinding wheel and angularly oscillating the'forrndressing. tool.

Still other objects; features and advantages of the present invention will become readily apparent from the following, detailed. description. of the principles and an embodiment thereof, from the claims, and: from the accompanying drawings, in which each and every detail shown is fully and completely disclosed as apart of this specification, whereinlike reference numerals refer to like parts, and wherein:

Figure 1 is a broken plan-viewof dressing apparatus embodying the principles of the present invention and shown in: cooperating position with a grinding wheel to be dressed; and

Figure 2 is a broken elevational view of a portion of the apparatus viewed substantially as taken along the line Ili--II of Figure 1.

As shown on the drawings:

When dressing grinding wheels or the like ontsuch installations as single. grinding wheel devices or multiple grinding wheel devices, such as centerless grinders, it is important that they be dressed highly accurately. The accuracy of the dressing of the grinding; wheel is determinative of the accuracy of the finished product and the trueness of the. configuration thereof to the desired configuration. In view of this circumstance, it is frequently necessary to redress agrinding wheel. at various intervals during theuse thereof in grindingfinished products. It, therefore, becomes necessary that the dressing operation be done as efficientlyaand' economically as possible and yet as accurately as possible; so; that while the finished product has the accuracy desired, the cost of production thereof does not become prohibitive.

To this-end, the present invention provides an economical, efiicient and highly accurate methodgand apparatus for dressing a grinding wheelsuch as the grinding wheel 10 so as to provide the same with. an accurate peripheral contour 11 as frequently as necessary. The: grinding wheel 10 may be mounted on any particular type of grinder d3, sired and the grinder is therefore illustrated more or less diagrammatically by the box' 12' which would'necessarily include driving meanstodrive the wheel shaft or spindle 13 carrying the. grinding wheel 10. which is. locked thereon by'such convenient means as: nuts: 14. and 15 or the like threaded onto the spindle or shaft.

In the instant case the. grinding wheel 10 is shown as having a peripheral. contour with. a. cylindrical axial shoulder 16 adjacent to one edge 17 of the wheel and adjacent to a radial face 18 which extends outwardly to an axial relatively short face 19. Progressively acrossthe periphery 11 of the grinding wheel, the periphery is further contoured with arcuate variations 20, 2'1 and 22: leading to a last axial shoulder or face 23 adjacent to the other radial face 24' on the grinding wheel 10. This particular peripheral configuration is exemplary only, since methods and apparatus for dressing grinding wheels in accordance with the present invention are not restricted:

to any particular facial configuration but may be utilized.

to form dress any desired peripheral configuration on a grinding wheel. The grinding wheel itself maybe of any desired manufactured characteristic such as a resin bonded wheel or the like.

To dress the periphery 11 of the grinding wheel accurately to its desired configuration, however, there is provided a dressing tool or dressing block. 25 which is mounted on the dressing mechanism spindle or support. arm 26 at the outer end thereof. This dressingmechanisrn.

' outer end thereof. a

spindle or support arm is mounted on the dressing mechanism, which is not critical to the present invention and therefore is illustrated diagrammatically by the box 27.

The dressing tool itself, however,- does form an inaportant part of this invention and While the composition thereof is not significant, it is important that 'it be shaped generally as acylinder segment, as shown in FigureZ, so that its dressing face 28 will be substantially cylindrical. That is, the dressing face itself will be configuratedperipherally reversely to the configuration of the periphery of the grinding wheel but each circumferential line on the arcuate face will be substantially a true circular arc with a radius equal to the distance between the line and the center of the oscillating shaft aperture 29 in the block. Still more particularly, the block or dressing tool 7 is a somewhat rectangular block having one arcuate face 28 and a shaft aperture 29 extending longitudinally through the block and so related to the arcuate face 28 as t'obealong the axis or center of curvature of the, face so that a peripheral line on the arcuate face 28 is a substantially true circular are having its center on the axis of the shaft aperture 29. An axle or otherequivalent pin 39 extends through the shaft aperture 29 and through an equivalent aperture 31 in the region of the outer end of the dressing spindle or support arm 26 to support the dressing tool 25 on the spindle or support arm at the The arcuate face 28 is the form' dressing'face of-the tool or block 25 and, as stated hereinbefore, is'configurated with peripheral variations corresponding, reversely,

to the faces and'variations in the periphery of the grinding wheel 10 so that it is'provided with an axial outwardly extending shoulder 16' adjacent to one end face thereof and further adjacent to a radial face 18" which extends radially inwardly to a second axially extending face 19' that progressively leads to arcuate variations 20121. and 22'. 1 i 7.

Adjacent to the other end face 32 of the blank 25, the periphery 28 is'provided with an axially extending face 23' corresponding to the face 23 on the grinding wheel 10. The dressing face 28 of the dressing tool 25 is impregnated with a layer of abrading diamonds or the like which may vary in size from as small as diamonds pass- .ing through a 400 mesh screen to diamonds as large as 50 per carat, In a preferred construction the cutting surface or abrading surface 28 of the tool 25 is provided with a single particle thickness diamond layer thereon since the dressing tool will lose some of the accuracy thereof after having been used sufliciently to dull or wear down the diamond points on a top layer of diamonds.

In accordance with the principles ofthe present invention, to dress the grindingiwheel' 10 with the dressing tool 25, the dressing face 28 of the'dressing tool 25 and the periphery 11 of the grinding wheel .10 are brought into engagement with each other while the grinding wheel 19 is being rotatably driven, as by the mechanism '12. At the same time, the dressing tool' 25 is being arcuately oscillated about its axis 'or the axis of the tool shafti'etl by an actuating mechanism which includes a'link 33 that is pinned or'otherwise secured to the tool, as indicated at 34 0135 and which has one end 36 thereof fixed on the tool-supporting shaft 30. :The other'or. outer. end .37 is pinned to the actuating arm 38 for rocking movement with respect thereto so that reciprocatory motion of the arm 38 which may be imparted thereto by any convert ient reciprocating mechanism schematically illustrated at 39, and which may be such a mechanism as'a cam mechanism or an hydraulic'or an electric :or other mechanical eccentric mechanism, willcause oscillating motion of the link33. 1

Such relative oscillatory movement of the link'33iwill the tool between the positions 40 and 41 the form dressing I face 28 thereof will be bidirectionally arcuately oscillated as indicated by the double headed arrows 42 and 43 so that it will oscillate on the rotating peripheral face 11 of the grinding wheel 10 and thereby truly form dress the described or any other desired periphery thereon most economically and efficiently. t i 7 While the outer end of the supporting spindle or arm 26 is curved, as at 44, to permit rotational oscillation of the form dressing tool 25 and the rearward face of the tool is channeled as at 45 to receive the outer end of the support arm 26, it will be understood that tnodification and variation of this structure and various other parts of the mechanism described and various details of the process described may be made without departing from the true spirit and scope of the novel concepts and principles of this invention. We, therefore, intend to cover all such modifications and variations as'fall within the true spirit and scope of the novel'concepts and principles of thisin'vention. V

We claim asou'r invention: a

1. In form dressing apparatusfor form dressing a grinding wheel to the desired'contour of its peripheral.

working face, means for rotating said wheel about its axis, a formdressing tool having an arcuate abrasive face of a transverse non-rectilinear contour the reverse of that'to be imparted to said grinding wheel working face, means pivotallymounting said toolabout an axis Wheel face while-in. abrading contact with said wheel face, said arcuate abrasive facehaving finely divided abrasive particles equivalent to diamonds ofa finenessof 50 particles per carat and finer embedded therein.

2. In a form dressing apparatus as defined by claim 1, the improvement which comprises means rigidly and tool about its axis While in abrading contact with said wheel face. J 3. In form dressing apparatus for form dressing a grinding wheel to the desired contour of its peripheral Working face, means for'rotating said 'wheel about its axis, a form dressing tool having an arcuate'abrasive face of a transverse non-rectilinear contour the reverse of that to be imparted to said grinding wheel working face, means pivotally mounting said tool about an axis parallel to the axis of said Wheel and including the centers of curvature of all circular arcs in said arcuate' face, and a rocking arm rigidly secured to said tool for driving said arcuate face at differential speeds. with respect to said wheel face while in abrading contact with be imparted to the tool 25through the pins 34 and 35 and the tool shaft 30 sothat the tool'will angularly oscillate betweenthe two phantom line positions shown therefor'and indicated generally at 40' and 41; By oscillating said wheel face, said arcuate abrasive face having finely divided abrasive particles equivalent to diamonds of a fineness of Sit-particles 'per carat and finer embedded therein. V

4. ha form dressing apparatus such as defined by claim 3, means including a link rigidly and ec'centrically affixed to thetool and areciprocably actuatable arm pivotally connected to said link to oscillate said link and. said tool about the axis'of said tool while the latter is in abrading contact {with said Wheel face. 7

' 5. In form dressing apparatus for form dres'sing a grinding Wheel to the desired contourof its-peripheral working face, means for rotating said wheel about its axis, a form dressi g toolhaving an arcuate abrasive face of atransverse non-rectilinear contour the reverse of that to be imparted to said grinding wheel Working face, means pivotally mounting said tool about an axis parallel to the" axis of said wheel and including the centers of curvature of all circular arcs in said arcuate face, and means secured to 'said tool to drive said arcuate face at differential speeds with respect to said wheel face while in abrading contact with saidwheel face, said arcuate abrasive face having finely divided abrasive particles equivalent to diamonds of a fineness of 50 particles per carat and finer embedded therein, said abrasive particles being in a surface layer of substantially a single particle thickness.

6. In a form dressing apparatus such as defined by claim 5, means for oscillating said tool about its axis including an axle pin for supporting said tool, a link carried on said axle pin and eccentrically secured to said tool for movement therewith, and a reciprocably actuable arm pivotally connected to said link for oscillating said link in said tool about the latters axis while the abrasive face of said tool is in abrading contact with said wheel face.

References Cited in the file of this patent UNITED STATES PATENTS 1,158,691 Knowlton Aug. 3, 1915 1,238,612 Wilson Aug. 28, 1917 2,252,096 Pew Aug. 12, 1941 2,398,022 Marren Apr. 9, 1946 2,450,237 Indge Sept. 28, 1948 2,778,170 Flanders Jan. 22, 1957 

